Bug 1711872 - Implement Object.hasOwn proposal; r=evilpie

Differential Revision: https://phabricator.services.mozilla.com/D115483

js/src/builtin/Object.cpp

@@ -2109,6 +2109,10 @@ static const JSFunctionSpec object_static_methods[] = {
     JS_FN("seal", obj_seal, 1, 0),
     JS_FN("isSealed", obj_isSealed, 1, 0),
     JS_SELF_HOSTED_FN("fromEntries", "ObjectFromEntries", 1, 0),
+/* Proposal */
+#ifdef NIGHTLY_BUILD
+    JS_SELF_HOSTED_FN("hasOwn", "ObjectHasOwn", 2, 0),
+#endif
     JS_FS_END};
 
 static JSObject* CreateObjectConstructor(JSContext* cx, JSProtoKey key) {

js/src/builtin/Object.js

@@ -323,3 +323,12 @@ function ObjectFromEntries(iter) {
     return obj;
 }
 
+// Proposal https://github.com/tc39/proposal-accessible-object-hasownproperty
+// 1. Object.hasOwn ( O, P )
+function ObjectHasOwn(O, P) {
+    // Step 1.
+    var obj = ToObject(O);
+    // Step 2-3.
+    return hasOwn(P, obj);
+}
+

js/src/tests/jstests.list

@@ -53,7 +53,6 @@ skip-if(!this.hasOwnProperty("Intl")) include test262/intl402/jstests.list
 skip-if(!this.hasOwnProperty("Atomics")) include test262/built-ins/Atomics/jstests.list
 skip-if(!this.hasOwnProperty("SharedArrayBuffer")) include test262/built-ins/SharedArrayBuffer/jstests.list
 
-
 #####################################
 # Test262 tests disabled on browser #
 #####################################
@@ -1018,3 +1017,4 @@ shell-option(--enable-iterator-helpers) script non262/Iterator/prototype/take/le
 shell-option(--enable-iterator-helpers) script non262/Iterator/prototype/take/name.js
 shell-option(--enable-iterator-helpers) script non262/Iterator/prototype/take/take.js
 shell-option(--enable-iterator-helpers) script non262/Iterator/prototype/take/take-more-than-available.js
+

js/src/tests/non262/object/hasOwn.js

@@ -0,0 +1,19 @@
+// |reftest| skip-if(!Object.hasOwn)
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * https://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+assertEq(Object.hasOwn({}, "any"), false);
+assertThrowsInstanceOf(() => Object.hasOwn(null, "any"), TypeError);
+
+var x = { test: 'test value'}
+var y = {}
+var z = Object.create(x);
+
+assertEq(Object.hasOwn(x, "test"), true);
+assertEq(Object.hasOwn(y, "test"), false);
+assertEq(Object.hasOwn(z, "test"), false);
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);

js/xpconnect/tests/chrome/test_xrayToJS.xhtml

@@ -229,6 +229,9 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=933681
                       "preventExtensions", "freeze", "fromEntries", "isFrozen", "seal",
                       "isSealed", "assign", "getPrototypeOf", "values",
                       "entries", "isExtensible"]);
+  if (isNightlyBuild) {
+    gConstructorProperties['Object'].push("hasOwn");
+  }
   gPrototypeProperties['Array'] =
     ["length", "toSource", "toString", "toLocaleString", "join", "reverse", "sort", "push",
       "pop", "shift", "unshift", "splice", "concat", "slice", "lastIndexOf", "indexOf",